Within the field of metal cutting tools used for grooving and turning operations, a cutting insert of typically small width and manufactured from a first material may be removably secured to a slotted portion of an insert holder having a similarly small width and manufactured from a second material, the first material being harder than the second material. Cutting forces are generally transmitted through the insert tip and the forward section of the insert holder lower surface, although in some grooving and turning operations a transverse component of the cutting force may initiate lateral displacement of the cutting insert with respect to the insert holder.
U.S. Pat. No. 6,086,291 discloses a cutting tool for parting and grooving operations where the insert holder includes a slot shaped insert seat with upper and lower V-shaped male parts and the cutting insert includes corresponding V-shaped female parts. Each V-shaped male part has a ridge with side surfaces forming an acute angle longitudinally extending between two laterally spaced apart first contact surfaces forming an obtuse wedge angle, and each V-shaped female part has a flute with side surfaces forming an acute angle longitudinally extending between two laterally spaced apart second contact surfaces forming an obtuse wedge angle.
The cutting insert and insert holder are manufactured such that when the insert is mounted in the insert seat, clamping contact is made between the V-shaped male and female parts at the first and second contact surfaces and a small gap is established between the ridge and flute side surfaces. In an operative mode, main forces are directed through the wider obtuse angled first and second contact surfaces, and transverse forces may be directed through the narrower acute angled ridge and flute side surfaces causing one of the ridge side surfaces to make contact with a corresponding flute side surface and absorb the transverse forces.
As the insert holder is configured with narrower acute angled ridges longitudinally extending between the wider obtuse angled first contact surfaces, undesirably difficult and time-consuming machining operations may be required to manufacture the insert holder.
Also, as the ridges and flutes longitudinally extend between the first and second contact surfaces of the V-shaped male and female parts, respectively, this may necessitate an undesirably large distance between the two laterally spaced-apart clamping contact locations on each of the V-shaped male and female parts.
U.S. Pat. No. 7,384,218 discloses a clamping mechanism for an insert detachable tool used for grooving and cutting-off operations, where a cutting insert is detachably mounted on an insert mounting seat of a holder. The insert mounting seat includes upper and lower jaws with V-shaped contacting surfaces extending in a longitudinal direction, where each contacting surface has a first pair of inclined planes and at least one of the contacting surfaces includes a guide part having a second pair of inclined planes.
The cutting insert has top and bottom surfaces with V-shaped contact surfaces which make clamping contact with the contacting surfaces of the upper and lower jaws, respectively, where each contact surface has a pair of convex surfaces with roundness to form a first pair of contacting positions when viewed in cross-section. There is typically no contact between the contact surfaces of the cutting insert and the second pair of inclined planes of the at least one guide part during clamping, although transient contact may occur at a second pair of contacting positions on at least one of the pairs of convex surfaces to smoothly guide and ensure alignment of the cutting insert during assembly to the holder. Also, during a cutting operation where a large load is applied to the cutting insert in the width direction, contact may occur at a second pair of contacting positions on at least one of the pairs of convex surfaces to stably hold the insert.
As the cutting insert is configured with the second pair of contacting positions between the first pair of contacting positions in the width direction, this may necessitate an undesirably large distance between the first pair of contacting positions.